Method for increasing the efficiency of diesel-electric driven vehicles, and vehicle for carrying out the method

ABSTRACT

In a method for increasing the efficiency of a consist comprised of a plurality of linked diesel-electric driven vehicles, with each vehicle including a diesel assembly and an intermediate circuit which is operatively connected to the diesel assembly and a drive motor which is operatively connected to the intermediate circuit, the operation of the diesel assembly of a vehicle is deactivated, when the vehicle requires a reduced level of power, while the vehicle is in travel mode. The drive motor is hereby operated in a regenerative mode and solely responsible, when operating in the regenerative mode, to feed electric energy to the intermediate circuit of the deactivated diesel assembly and an auxiliary operating device, connected to the intermediate circuit.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application claims the priority of German Patent Application,Serial No. 10 2006 042 945.1, filed Sep. 13, 2006, pursuant to 35 U.S.C.119(a)-(d), the content of which is incorporated herein by reference inits entirety as if fully set forth herein.

BACKGROUND OF THE INVENTION

The present invention relates to a method and apparatus for increasingthe efficiency of a consist comprised of a plurality of diesel-electricdriven vehicles.

Nothing in the following discussion of the state of the art is to beconstrued as an admission of prior art.

Freight trains are often operated with multiple traction, i.e. a freighttrain is driven by a number of diesel locomotives. Depending on theacceleration behavior and terrain to be negotiated, the diesel drives ofthe diesel locomotives are hereby not operated at full power at alltimes. However, operating a diesel assembly in partial load rangeadversely affects efficiency.

When freight trains are operated with multiple traction, the diesellocomotives are normally used with one large diesel engine perlocomotive without control or voltage connections between thelocomotives. In other words, even when the power demand is relativelylow, such as for example when traveling downhill for an extended period,the diesel assemblies of each locomotive have to be kept operational inorder to provide sufficient energy, for example in order to operate thebrake system of the locomotive.

The publication “Intelligent Power Sharing within a Locomotive Consistfor Fuel Reduction and Trip Reliability Enhancements” (Gritsch et al.,Heavy Haul Conference, Brazil, 2005), discloses the linkage of aplurality of diesel locomotives with an electric drive to realize aconsist in which the intermediate circuits of all the locomotives areconnected to one another. Connecting the intermediate circuits of allthe locomotives to one another makes it possible to transfer theelectric power produced at one locomotive to another locomotive and thusto feed the required power from just a small number of diesel assembliesinto the overall intermediate circuit and switch off the remainingdiesel assemblies. In other words, when a relatively low level of poweris required, a number of diesel locomotives travel with activated dieselassemblies and other diesel locomotives travel with deactivated dieselassemblies, whereby the required energy of one locomotive with thedeactivated diesel assembly is transferred from locomotives withactivated diesel assemblies to locomotives with deactivated dieselassemblies to maintain the auxiliary operations, for example the brakesystems and the temperature maintenance of the diesel assemblies. At thesame time, the full starting tractive force is maintained since all thedrives of each locomotive can also be provided with power by virtue ofthe connection of the intermediate circuits, and therefore all thedrives can also be active during starting. Diesels which are deactivatedin the travel mode can optionally be started up again by means of aconverter or its intermediate circuit. However, high voltage couplingpoints in the region of the locomotive couplings have to be provided inorder to be able to connect the intermediate circuits of the locomotivesto one another. These high voltage lines usually conduct a voltage ofapproximately 2000 volts, which has to be isolated for safety reasonswhen the coupling point is not used. The connection of the intermediatecircuits complicates the overall construction and requires appropriatesafety measures.

It would therefore be desirable and advantageous to address this problemand to obviate other prior art shortcomings.

SUMMARY OF THE INVENTION

According to one aspect of the present invention, a method forincreasing the efficiency of a consist comprised of a plurality oflinked diesel-electric driven vehicles, with each vehicle including adiesel assembly and an intermediate circuit which is operativelyconnected to the diesel assembly and a drive motor which is operativelyconnected to the intermediate circuit, includes the steps ofdeactivating operation of the diesel assembly of a vehicle, when thevehicle requires a reduced level of power, while the vehicle is intravel mode, operating the drive motor in a regenerative mode, andfeeding electric energy to the intermediate circuit of the deactivateddiesel assembly and an auxiliary operating device, connected to theintermediate circuit, solely by the drive motor, as it operates in theregenerative mode.

In the normal travel mode, when the diesel assembly is activated, themain generator of the locomotive which is connected downstream of thediesel assembly in order to generate electric energy feeds the auxiliaryoperating devices which are connected to an intermediate circuit. In thetravel mode, on the other hand, when the diesel assembly is deactivated,the drive motors can be operated as generators and thus feed theintermediate circuit. The thus-produced energy can be used to restartthe diesel engine and to maintain the operating temperature and tosupply power to individual, relatively small consumers such as, forexample, pumps, fans or lighting systems. As a result, efficiency ofdiesel drives of a plurality of vehicles traveling with multipletraction can be increased, and, when a specific reduced level of poweris required of the vehicles which are traveling in a consist, at leastone diesel assembly of one of the vehicles is deactivated. The power formaintaining the auxiliary operations and for restarting the dieselassemblies can thus be transmitted indirectly from one locomotive toanother locomotive by converting the mechanical energy of the wheels andthe regeneratively operating drive motors.

In accordance with the invention, it is thus possible to switch off thediesel assembly when n vehicles (multiple traction) are operating andthere is a request for a reduced locomotive power of up to n−1 vehicles.The regenerative operation of the drive motors allows the auxiliaryoperations to be provided with electric energy on the vehicle with thediesel assembly deactivated. The possibility of deactivating individualdiesel assemblies while maintaining the full driving power results incost saving and reduces wear of the diesel assemblies since a dieselassembly can be switched off, when the power demand is low, and does nothave to be operated in the unfavorable partial load range. As a result,fuel consumption can also be reduced.

According to another feature of the present invention, the dieselassembly can be deactivated automatically when the level of powerreaches a lower limit. In other words, when the power drops below aspecific value, the associated diesel assembly switches offautomatically. Suitably, the diesel assembly switches on againautomatically, when the lower power limit is exceeded again.

According to another feature of the present invention, the drive motormay provide electric energy that is commensurate with a power demandconsumed by the auxiliary operating device. When, for example, theexternal temperature is high, less energy is necessary to maintain aspecific operating temperature of the diesel assemblies. Suitably, theregeneratively operating drive motors produces correspondingly lesspower to maintain the operating temperature. As a result of thisconfiguration, the regeneratively operating drive motors have a reducedbraking effect, which leads to a further increase in efficiency duringoperation of the vehicle and in the case of multiple tractions.

According to another feature of the present invention, the method stepscan be realized under the control of a control unit. Thus, the fullyautomated deactivation and restarting of the diesel assemblies inresponse to the power demand, as well as the control of the drives canbe executed in a controlled manner such that only energy is supplied asis necessary to maintain the auxiliary operations and the operatingtemperature of the diesel assembly.

According to another aspect of the present invention, a vehicle includesat least one diesel assembly, a generator connected to the dieselassembly for feeding electric energy to an intermediate circuit, atleast one converter coupled to the intermediate circuit, at least oneauxiliary operating device coupled to the intermediate circuit, and adrive motor receiving electric energy from the converter and constructedfor operation in a motor mode and regenerative mode, wherein the drivemotor operates in the regenerative mode, when the diesel assembly isdeactivated while the vehicle is in travel mode, so that theintermediate circuit and the auxiliary operating device are fedexclusively by the drive motor with electric energy.

As already described above, the regenerative mode of the drive motor isthe operating mode as a generator. When operating as a generator, thedrive motor feeds electric energy into the respective intermediatecircuit. This electric energy is used in the intermediate circuit torestart the diesel assembly and to maintain the desired operatingtemperature of the diesel assembly for restarting, as well as tomaintain specific auxiliary operations. Since the mechanical energy ofthe wheels is converted into electrical energy, when the vehicle travelswith the diesel assembly deactivated, the electrical energy which isgenerated by a locomotive in multiple traction mode can be convertedinto mechanical energy and supplied to another locomotive by virtue ofthe conversion of the mechanical energy into electrical energy.

The converter may be implemented as a pulse-controlled inverter, i.e. anactive rectifier. Suitably, at least one inverter, which feeds at leastone drive motor, may be connected in the intermediate circuit. It isthus possible, to deactivate n−1 locomotives or their diesel assemblies,when multiple traction is involved and a reduced level of traction poweris required by n vehicles which are each equipped with a dieselassembly. The supply to the auxiliary operations on the other vehiclesis maintained by the regenerative operation of the drives.

According to another feature of the present invention, a control levelmay be provided having at least one connection for connecting thecontrol level to a control level of a further vehicle in the absence ofa high voltage connection of the intermediate circuit to an intermediatecircuit of the further vehicle. By means of the control level with itsconnecting points, it is possible for at least one diesel assembly on aspecific vehicle to be activated or deactivated or switched to a standbymode. In this context, it is possible for the diesel assembly of aspecific locomotive to be switched off or on from a central locationwith overall control of the locomotives. There is no need to connecthigh voltage lines of the locomotives to one another because the powersupply for the auxiliary operations and for restarting the dieselassembly is provided in the travel mode of the deactivated locomotive bymeans of the regenerative operation of its drive motors. As the highvoltage lines of the locomotives are not connected to one another, thereare also no coupling points for producing such connections. In otherwords, conventional mechanical couplings can be provided between thelocomotives, and connections of low voltage lines can be used foroperating relatively small assemblies such as, for example, fans, pumpsand lighting devices and possibly couplings of pressure lines, withoutthe need for coupling points for the high voltage line of anintermediate circuit for connecting the intermediate circuit to theintermediate circuit of another locomotive.

The intermediate circuit of each diesel assembly of a locomotive thusdoes not have branches. The elimination of a high voltage connectionremoves also the need for costly isolation of approximately 2000 voltswhich would be required, when the assembly is not in use, and necessaryfor safety reasons, so that the structural design of the vehicle issimplified.

According to another feature of the present invention, a control unitmay be provided for switching the diesel assembly on or off via thecontrol level in dependence on the power demand, and for controlling thedrive motor in the regenerative mode such that the drive motor providesonly power that is commensurate with a need by the auxiliary operatingdevices. In other words, the control unit manages the deactivation andrestarting of the diesel engines in the case of a corresponding powerdemand, as well as the control of the drives, in such a way that theyonly supply as much energy as is necessary to maintain the auxiliaryoperations and the operating temperature of the diesel assembly and torestart the diesel assembly. The control unit can influence theassemblies of any of the locomotives which are traveling in consist orcan control them by connecting the control levels of vehicles whichtravel in multiple traction.

According to another feature of the present invention, two dieselassemblies may be provided, wherein the generators of the dieselassemblies jointly feed a common intermediate circuit. This doublearrangement of diesel assemblies on one vehicle allows that one of thetwo diesel engines can be deactivated or operate in a standby mode (inparticular when a reduced level of power is required), and, when thepower demand drops even further, a second diesel engine can also bedeactivated. As a result of the regenerative operating mode of the drivemotors, both diesel engines whose intermediate circuits are independentof one another can be started again by means of their regenerativelyoperating drive motors, or their auxiliary operating devices are fed bythe regeneratively operating drive motors. It is thus possible toprovide, in a vehicle which is provided with two diesel assemblies, thatwhen the intermediate circuits of the diesel assemblies are disconnectedentirely, the power supply of one auxiliary circuit of one deactivateddiesel assembly is provided exclusively by means of the conversion ofthe mechanical energy of the wheels into electrical energy in order tofeed the intermediate circuit when the diesel assembly is deactivated.

According to another feature of the present invention, two inverters maybe arranged at the intermediate circuit, with each of the invertersfeeding up to three drive motors on one bogie. Thus, for example, eachof the inverters may feed three drive motors which are arranged on onebogie. As a result, even when just one diesel assembly is operating,voltage is available for operating both drive converters and all themotors can supply the full starting torque. At startup, just one dieselassembly is required to operate, either on a locomotive with a pluralityof diesel assemblies or in a consist of vehicles operating in multipletraction in which individual locomotives or their diesel assemblies aredeactivated.

According to another feature of the present invention, the generator ofthe vehicle may be configured for operation in motor mode as a starterof the diesel assembly. As a result, the intermediate circuit which isfed via the regeneratively operating drive motors supplies the power forstarting the diesel assembly by means of the vehicle's generator whichis operated as a starter. For this purpose, the generator may have anactive rectifier.

The rectifier which is connected downstream of the generator in thenormal travel mode may serve as a pulse-controlled inverter for thegenerator which functions as a starter.

According to another feature of the present invention, there may beprovided a battery, and a DC/DC converter which connects the battery tothe intermediate circuit. As a result, when no energy is stored in theintermediate circuit as of yet during initial startup of the diesellocomotive, the diesel locomotive can be started by the electric energyfrom the battery via the DC/DC converter and the generator whichfunctions as a starter. The DC/DC converter can be configured in such away that it can be used as a battery charging device in the normaltravel mode.

According to another feature of the present invention, the auxiliaryoperating device may include an auxiliary operating converter and apulse-controlled inverter which is configured for driving the generatorwhich functions as the starter of the diesel assembly. The auxiliaryoperating converter is used when supplying power to the auxiliaryoperating devices.

According to another feature of the present invention, the generator ofthe vehicle may be configured as a permanently excited synchronousmachine. This enables efficient operation of the vehicle in a simplemanner.

BRIEF DESCRIPTION OF THE DRAWING

Other features and advantages of the present invention will be morereadily apparent upon reading the following description of currentlypreferred exemplified embodiments of the invention with reference to theaccompanying drawing, in which the sole FIGURE shows a schematicillustration of a consist with three diesel-electric driven locomotivesoperated with multiple traction.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The depicted embodiment is to be understood as illustrative of theinvention and not as limiting in any way. It should also be understoodthat the FIGURE is not necessarily to scale and details which are notnecessary for an understanding of the present invention or which renderother details difficult to perceive may have been omitted.

Turning now to the FIGURE, there is shown a consist with vehicles 1 inthe form of three diesel-electric driven locomotives which are coupledto one another mechanically. Each of the vehicles 1 has a dieselassembly 2 as well as a generator 3, a converter 4, an auxiliaryoperating device 5, and a plurality of drive motors 6 which are arrangedon bogie 9. One of the vehicles 1 is equipped with a control unit 7,which is connected to the control level 8 of the vehicle 1. The controllevel 8 is connected in series with the control levels 8 of the furthervehicles 1.

Furthermore, each of the vehicles 1 has an auxiliary operating converter10 and a heating resistor 11. The heating resistor 11 serves to maintainthe operating temperature of the diesel assembly 2 when power issupplied.

When reduced power levels are required in travel mode, the control unit7 is able to transmit, via the control levels 8, a signal to the dieselassembly 2, for example of the middle vehicle 1, so that this dieselassembly 2 is deactivated. The electric drives 6 which are arranged onthe bogie 9 are no longer supplied with electric energy from this momenton and they no longer drive the wheels of the vehicle 1. However, as aresult of the fixed mechanical connection of the wheels of the vehicle 1to the drive motors 6, the rotational parts of the drive motors 6 arestill moving and thus operate in a generator mode of the drive motor 6.The electric energy generated in the generator mode is fed into anintermediate circuit 2 a of the vehicle 1. Only the intermediate circuit2 a of the middle vehicle 2 is shown here schematically, by way ofexample, for the sake of simplicity. The auxiliary operating device 5 issupplied with energy via the auxiliary operating converter 10 to feed,for example, the heating resistor 11 of the vehicle 1 in order tomaintain the desired operating temperature of the diesel assembly 2.However, it is also possible to feed the heating resistor 11 withelectric energy directly via the intermediate circuit 2 a which isconnected to the heating resistor 11.

At startup of the diesel assembly 2, the energy which is stored in theintermediate circuit 2 a is fed to the generator 3 which functions as astarter in this case. Thus, the vehicle 1 can be restarted by the energygenerated by the drive motors 6, while the vehicle 1 with deactivateddiesel assembly 2 travels.

As a result, there is no need for a connection of the high voltageregions or of the intermediate circuits 2 a of the vehicle 1 to theintermediate circuits 2 a of connected vehicles 1 since the electricenergy which is necessary to restart or to maintain the auxiliaryoperations is acquired from the mechanical energy which is present inthe travel mode and is converted. Therefore, there is also no need forcoupling points for high voltage systems to be arranged in themechanical coupling region of the vehicles 1.

While the invention has been illustrated and described in connectionwith currently preferred embodiments shown and described in detail, itis not intended to be limited to the details shown since variousmodifications and structural changes may be made without departing inany way from the spirit of the present invention. The embodiments werechosen and described in order to best explain the principles of theinvention and practical application to thereby enable a person skilledin the art to best utilize the invention and various embodiments withvarious modifications as are suited to the particular use contemplated.

1. A method for increasing the efficiency of a consist comprised of aplurality of linked diesel-electric driven vehicles, each vehicleincluding a diesel assembly and an intermediate circuit which isoperatively connected to the diesel assembly and a drive motor which isoperatively connected to the intermediate circuit, said methodcomprising the steps of: a) deactivating operation of the dieselassembly of a vehicle, when the vehicle requires a reduced level ofpower, while the vehicle is in travel mode; b) operating the drive motorin a regenerative mode; and c) feeding electric energy to theintermediate circuit of the deactivated diesel assembly and an auxiliaryoperating device, connected to the intermediate circuit, solely by thedrive motor, as it operates in the regenerative mode.
 2. The method ofclaim 1, wherein the diesel assembly is deactivated automatically whenthe level of power reaches a lower limit.
 3. The method of claim 1,wherein the drive motor provides electric energy that is commensuratewith a power demand consumed by the auxiliary operating device.
 4. Themethod of claim 1, further comprising the step of using a control unitfor a realizing a controlled operation of steps a) to c).
 5. A vehicle,comprising: at least one diesel assembly; a generator connected to thediesel assembly for feeding electric energy to an intermediate circuit;at least one converter coupled to the intermediate circuit; at least oneauxiliary operating device coupled to the intermediate circuit, and adrive motor receiving electric energy from the converter and constructedfor operation in a motor mode and regenerative mode, wherein the drivemotor operates in the regenerative mode, when the diesel assembly isdeactivated while the vehicle is in travel mode, so that theintermediate circuit and the auxiliary operating device are fedexclusively by the drive motor with electric energy.
 6. The vehicle ofclaim 5, further comprising a control level with at least one connectionfor connecting the control level to a control level of a further saidvehicle in the absence of a high voltage connection of the intermediatecircuit to an intermediate circuit of the further vehicle.
 7. Thevehicle of claim 6, further comprising a control unit for switching thediesel assembly on or off via the control level in dependence on thepower demand, and for controlling the drive motor in the regenerativemode such that the drive motor provides only power that is commensuratewith a need by the auxiliary operating devices.
 8. The vehicle of claim5, further comprising two of said diesel assembly, wherein thegenerators of the diesel assemblies jointly feed the intermediatecircuit with is common to both diesel assemblies.
 9. The vehicle ofclaim 5, further comprising two inverters arranged at the intermediatecircuit, wherein each of the inverters feeds up to three drive motors ona bogie.
 10. The vehicle of claim 5, wherein the generator is configuredfor operation in motor mode as a starter of the diesel assembly.
 11. Thevehicle of claim 10, further comprising a rectifier connected downstreamof the generator in normal travel mode and serving as a pulse-controlledinverter for the generator which functions as the starter of the dieselassembly.
 12. The vehicle of claim 5, further comprising a battery, anda DC/DC converter which connects the battery to the intermediatecircuit.
 13. The vehicle of claim 12, wherein the DC/DC converter isconfigured for use as a battery charging device in normal travel mode.14. The vehicle of claim 10, wherein the auxiliary operating deviceincludes an auxiliary operating converter and a pulse-controlledinverter which is configured for driving the generator which functionsas the starter of the diesel assembly.
 15. The vehicle of claim 5,wherein the generator is a permanently excited synchronous machine. 16.A consist, comprising a plurality of track-bound vehicles which arecoupled to one another, each said vehicle supported for mobility on thetrack by a bogie, a diesel assembly, and a drive motor mounted in thebogie and operatively connected to the diesel assembly via anintermediate circuit, said drive motor being constructed for operationin a motor mode, in which the diesel assembly is operative so that theintermediate circuit is supplied with electric energy from a generatorconnected to the diesel assembly, and a regenerative mode, in which thediesel assembly is deactivated and the intermediate circuit is suppliedwith electric energy solely from the drive motor during movement of thebogie.